Our long term goal of the research on the potential tumor suppressor protein p63 is to understand the different biological functions of the p53 and p63 in cell cycle control and apoptosis. One of the key differences between the two proteins is the existence of regulatory domains in p63 which control its oligomerization state and its DNA binding activity. Domains with similar functions have not been identified in p53. Characterization of these domains and their functions will, therefore, provide important information about the different roles that both proteins play in cell cycle control and induction of apoptosis. Furthermore, detailed understanding of the functions of p53 and p63 might lead to the development of new tumor therapy strategies based on selective activation of p63 in p53-deficient tumor cells. As a first step in this direction we want to investigate the regulation of the activity of p63 by its N-terminal and C-terminal domains. The short term goal of the proposed research is to determine the three-dimensional structure of the individual domains of p63 by NMR spectroscopy and to investigate the interactions between these domains. The analysis of these experiments necessitates the use of the hardware and software made available by the Computer Graphics Laboratory. Specifically, the NMR Data Analysis software will be used to assign and analyze the NMR data. The resulting structures will then be visualized and manipulated in order to further understand the function of the regulatory domains of the p63 protein.